JP7768183B2 - Transport System - Google Patents

Description

This disclosure relates to a conveying system.

Patent Document 1 discloses an autonomous vehicle that transports shelves to be transported. The shelves are provided with protrusions, and the autonomous vehicle is provided with engagement parts that engage with the protrusions on both the front and back of the shelf. The sensor used for docking control blocks light from a light-emitting part with the object to be detected, and receives the reflected light with a light-receiving part.

Japanese Patent Application Laid-Open No. 2022-144293

The robot's autonomous movement alone does not provide high positioning accuracy, so it may not be possible to mount shelves or other items. Since the light-emitting and light-receiving units are located on the bottom, accumulating dust or other particles can result in false detection.

The transport system according to this embodiment is a transport system comprising a mobile robot that moves carrying a wagon with multiple protrusions protruding downward. The mobile robot has a mounting surface on which the wagon is placed, a stage that enters below the wagon, an elevator mechanism that raises and lowers the stage to transfer the wagon, multiple recesses corresponding to the multiple protrusions, an optical sensor provided on the side of at least one of the recesses, and a detection unit that detects whether the protrusion is inserted into the recess based on the detection result of the optical sensor.

The above-mentioned transport system may compare the amount of light detected by the optical sensor with a threshold value to determine whether the insertion state is normal.

In the above-mentioned conveying system, the optical sensors may be provided in only some of the recesses.

In the above-mentioned conveying system, the tip of the convex portion may be curved and may become smaller as it approaches the tip.

The above-mentioned conveying system may have a tapered surface between the placement surface and the recess that widens as it goes upward.

In the above-mentioned conveying system, the recesses may be arranged diagonally on the placement surface.

In the above-mentioned conveying system, if the positioning convex portion does not fit into the concave portion, it may be determined to be a loading error and the system may move away for a while before retrying.

In the above-mentioned conveying system, the surface of the convex portion may be formed with a light-absorbing color.

The above-mentioned conveying system may further include the wagon.

This disclosure provides a transport system that can transport materials appropriately.

1 is a perspective view schematically showing the overall configuration of a mobile robot according to an embodiment of the present invention; FIG. 1 is a side view showing a configuration in which a mobile robot is equipped with a wagon. FIG. 4 is an enlarged cross-sectional view showing a detailed configuration of a positioning portion. FIG. 10 is an enlarged cross-sectional view showing a detailed configuration of the positioning unit when an abnormal mounting occurs. FIG. 10 is a side view illustrating a mounting abnormality. FIG. 2 is a block diagram showing a control system of the mobile robot. 10 is a flowchart showing the loading operation of the wagon.

The present invention will be described below through embodiments of the invention, but the invention as claimed is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential as means for solving the problem.

First Embodiment
FIG. 1 is a perspective view showing the overall configuration of a mobile robot 100 according to this embodiment. In the following explanation, an XYZ Cartesian coordinate system will be used where appropriate. The X direction is the front-to-back direction of the mobile robot 100, the Y direction is the left-to-right direction, and the Z direction is the vertical up-down direction. More specifically, the +X direction is defined as the front direction of the mobile robot 100, and the -X direction is defined as the rear direction of the mobile robot 100. The +Y direction is the left direction of the mobile robot 100, and the +Y direction is the left direction of the mobile robot 100. The +Z direction is the vertical up direction, and the -Z direction is the vertical down direction.

The mobile robot 100 can move both forward and backward. In other words, rotating the wheels forward causes the mobile robot 100 to move forward, and rotating them backward causes the mobile robot 100 to move backward. By changing the rotation speed of the left and right wheels, the mobile robot 100 can turn left and right.

The mobile robot 100 comprises a chassis 110, a stand 120, and an operation unit 130. The chassis 110 is equipped with wheels, axles, a battery, a control computer, a drive motor, etc. The chassis 110 holds the wheels (not shown in FIG. 1) in a rotatable manner. Furthermore, the chassis 110 may be equipped with various sensors such as a camera and a distance sensor. Here, the mobile robot 100 will be described as an autonomous mobile robot. Of course, the mobile robot 100 may also be a mobile robot that moves in response to user operation.

The chassis 110 houses a lifting stage 140 for loading and unloading luggage. The lifting stage 140 is located on the upper side of the chassis 110. The lifting stage 140 is equipped with a lifting mechanism driven by a motor or the like. The chassis 110 has a built-in motor and guide mechanism for lifting. The upper surface of the lifting stage 140 serves as a loading surface 142 on which a wagon is placed. The lifting stage 140 has a lift mechanism for lifting the wagon. The space above the lifting stage 140 serves as a loading space for loading luggage. The chassis 110 is equipped with a rechargeable secondary battery.

The mounting surface 142 is, for example, a plane parallel to the XY plane. The height of the mounting surface 142 changes depending on the operation of the lifting stage 140. The mounting surface 142 is also provided with a positioning portion 141 for determining the mounting position of the wagon.

Here, two positioning portions 141 are formed on the mounting surface 142. The positioning portions 141 have recesses formed in the mounting surface 142. In other words, the positioning portions 141 are recessed portions below the mounting surface 142. As will be described later, the wagon is provided with a positioning pin that protrudes downward (toward the -Z side). The positioning pins are fitted into the recesses of the positioning portions 141, allowing the mounting position of the wagon to be determined. The detailed configuration of the positioning portions 141 will be described later.

Two positioning portions 141 are arranged diagonally on the mounting surface 142 when viewed in the XY plane. The two positioning portions 141 are arranged offset in the X direction. The two positioning portions 141 are arranged offset in the Y direction. In the XY plane, the positioning portions 141 are formed near the front right end and the rear left end of the mounting surface 142. In other words, on the mounting surface 142, one positioning portion 141 is located on the +X side and the -Y side, and the other positioning portion 141 is located on the -X side and the +Y side. This prevents misalignment, allowing the wagon 500 to be mounted stably. Specifically, it prevents misalignment in the rotational direction around the Z axis.

The stand 120 is attached to the chassis 110. The stand 120 is a rod-shaped member extending upward from the chassis 110. Here, the stand 120 is formed in a cylindrical shape with its longitudinal direction in the Z direction. The longitudinal direction of the stand 120 is set parallel to the Z direction. The stand 120 is positioned outside the lift stage 140. In other words, the stand 120 is positioned so as not to interfere with the lifting and lowering operation of the lift stage 140. The stand 120 is positioned at one end of the chassis 110 in the Y direction (left-right direction). The stand 120 is attached near the front left corner of the chassis 110. In the XY plane, the stand 120 is provided at the end of the chassis 110 on the +X side and the -Y side.

The stand 120 supports the operation unit 130. The operation unit 130 is attached near the top end of the stand 120. This allows the operation unit 130 to be installed at a height that is easy for a user to operate. In other words, the stand 120 extends to a height that is easy for a user to operate while standing. The operation unit 130 extends from the stand 120 to the +Y side. In the left-right direction, the operation unit 130 is located in the center of the chassis 110.

The operation unit 130 has a touch panel monitor that accepts user operations. Of course, the operation unit 130 may also have a microphone for voice input. The monitor of the operation unit 130 faces away from the chassis 110. In other words, the display surface (operation surface) of the operation unit 130 is the +X side. The operation unit 130 may be detachable from the stand 120. In other words, the stand 120 may be equipped with a holder that holds the touch panel. By operating the operation unit 130, the user can input the destination of the package, delivery information related to the package, etc. Furthermore, the operation unit 130 can display to the user information such as the package being delivered, the contents of the package, and the package to be delivered, as well as its destination.

A user places luggage (also called items or transported goods) in a wagon mounted on the mobile robot 100 and requests transportation. The mobile robot 100 autonomously moves to the set destination and transports the luggage. In other words, the mobile robot 100 executes a luggage transport task (hereinafter simply referred to as a task). In the following explanation, the location where the luggage is loaded will be referred to as the origin or loading location, and the location where the luggage is delivered will be referred to as the destination or destination.

For example, suppose the mobile robot 100 moves within a general hospital with multiple medical departments. The mobile robot 100 transports supplies, consumables, medical equipment, etc. between the multiple medical departments. For example, the mobile robot 100 delivers luggage from the nurse's station of one medical department to the nurse's station of another medical department. Alternatively, the mobile robot 100 delivers luggage from a storage room for supplies and medical equipment to the nurse's station of a medical department. The mobile robot 100 also delivers medicine dispensed in a pharmacy department to the medical department or patient that will use it.

Examples of cargo include consumables such as medications and bandages, specimens, testing equipment, medical instruments, hospital food, stationery, and other supplies. Medical equipment includes blood pressure monitors, transfusion pumps, syringe pumps, foot pumps, nurse call buttons, bed exit sensors, foot pumps, low-pressure continuous inhalers, electrocardiogram monitors, drug infusion controllers, enteral nutrition pumps, ventilators, cuff pressure gauges, touch sensors, aspirators, nebulizers, pulse oximeters, blood pressure monitors, artificial resuscitators, sterilization devices, and ultrasound machines. Food such as hospital meals and test meals may also be delivered. Furthermore, the mobile robot 100 may deliver used equipment, used tableware, and other items. If the delivery destination is on a different floor, the mobile robot 100 may travel using an elevator or other means.

Figure 2 is a side view showing the configuration of a transport system 1 equipped with a mobile robot 100 and a wagon 500. As shown in Figure 2, the mobile robot 100 can hold the wagon 500 using the lifting stage 140. The wagon 500 accommodates transported objects. The wagon 500 is provided with wheels 502 and a frame 503. The wheels 502 are attached to the underside of the frame 503.

A frame 503 extends below the wagon 500. This provides space below the wagon 500 for the chassis 110 to enter. In other words, the chassis 110 can enter the space directly below the wagon 500. When the chassis 110 is carrying the wagon 500, the mobile robot 100 moves in the -X direction and enters directly below the wagon 500.

The lifting mechanism raises and lowers the lifting stage 140, allowing the wagon 500 to be handed over. When the lifting stage 140 rises, the wagon 500 is lifted. In other words, when the lifting stage 140 rises, the wheels 502 lift off the ground and the wagon 500 is mounted on the chassis 110. When the lifting stage 140 descends, the wheels 502 come into contact with the floor surface and the top surface of the lifting stage 140 moves away from the wagon 500. The wagon 500 is placed on the floor surface. The wagon 500 can then be lowered from the chassis 110.

The chassis 110 is provided with one or more wheels 111. For example, in Figure 1, two wheels 111 are provided on the left and right, and in Figure 2, three wheels 111 are provided on the front and rear, but the number of wheels 111 is not particularly limited. For example, the mobile robot 100 may have four wheels, six wheels, or even eight or more wheels. The mobile robot 100 only needs to have one or more drive wheels that rotate with a motor. Furthermore, one or more of the multiple wheels 111 may be driven wheels. Then, by controlling the rotation of each wheel 111, the mobile robot 100 moves along a desired route.

The configuration of the positioning portion 141 will be explained using Figure 3. Figure 3 is an XZ cross-sectional view that schematically shows the positioning portion 141 and its surrounding configuration. The positioning portion 141 has a recess 145 and a tapered surface 143. The bottom surface of the wagon 500 is provided with a positioning pin 510 that protrudes downward. The positioning pin 510 has a cylindrical shape, and its tip portion 512 has a hemispherical curved surface.

A positioning pin 510 provided on the wagon 500 is inserted into the recess 145. The positioning pin 510 is a convex portion that protrudes downward. The recess 145 is a hole that is larger than the positioning pin 510. When the lifting stage 140 rises, the positioning pin 510 is inserted into the recess 145.

A number of recesses 145 are provided corresponding to a number of positioning pins 510. The recesses 145 are provided on the mounting surface 142 in a positional relationship that corresponds to the positional relationship of the positioning pins 510. These positioning pins 510 and recesses 145 have corresponding engagement structures. When mounting the wagon, one positioning pin 510 is inserted into one recess 145. One positioning pin 510 is inserted into one recess 145 in a corresponding positional relationship.

For example, recess 145 is a cylindrical hole with a diameter larger than that of positioning pin 510. A tapered surface 143 is provided between recess 145 and mounting surface 142. Tapered surface 143 widens as it goes upward. For example, tapered surface 143 is a mortar-shaped inclined surface. Tapered surface 143 has a shape corresponding to the side surface of a cone. When viewed from above, tapered surface 143 has a circular outer shape. Recess 145 is located at the center of tapered surface 143. The upper end of tapered surface 143 is connected to mounting surface 142, and the lower end is connected to recess 145. The diameter of tapered surface 143 widens as it goes from recess 145 to mounting surface 142. It is preferable that tapered surface 143 be a smooth surface with low friction.

Furthermore, a sensor 147 is disposed on the side of the recess 145. Specifically, an installation hole 146 is provided on the side of the recess 145. In this case, the installation hole 146 is a space extending in the X direction. The sensor 147 is disposed within the installation hole 146. The sensor 147 is disposed facing to the side.

Sensor 147 is an optical sensor such as a fiber sensor. For example, sensor 147 has a light-emitting unit and a light-receiving unit. The light-emitting unit emits light toward recess 145. In Figure 3, sensor 147 is located on the +X side of recess 145, so sensor 147 emits light in the -X direction. The light-receiving unit receives light from recess 145.

Here, if a positioning pin 510 is placed in the recess 145, the light emitted from the sensor 147 is incident on the positioning pin 510. A portion of the light reflected by the positioning pin 510 is reflected in the direction of the sensor 147. The sensor 147 detects the light reflected by the positioning pin 510. Therefore, the mobile robot 100 can detect that the positioning pin 510 is inserted into the recess 145. In other words, if the positioning pin 510 is not inserted into the recess 145, the amount of detected light will be extremely low. In this case, the mobile robot 100 determines that a loading error has occurred.

Furthermore, the insertion state of the positioning pin 510 can be determined based on the amount of reflected light detected by the sensor 147. Figure 3 shows the configuration in a normal mounting state (see Figure 2). Figure 4 shows the configuration in an abnormal mounting state. Specifically, in Figure 3, the positioning pin 510 is parallel to the Z direction, so the positioning pin 510 is inserted straight into the recess 145. On the other hand, in Figure 4, as shown in Figure 5, the mobile robot 100 mounts the wagon 500 in an inclined position, so the positioning pin 510 is inclined from the Z direction. Therefore, the positioning pin 510 is inserted into the recess 145 in an inclined position.

As shown in Figure 3, sensor 147 is positioned at the height of tip 512, which forms a curved surface. Therefore, sensor 147 detects light reflected by tip 512. The amount of reflected light detected by sensor 147 changes depending on the inclination of positioning pin 510. In Figure 4, positioning pin 510 reflects light in the -Z direction. Therefore, the amount of light detected by sensor 147 changes between the state shown in Figure 3 and the state shown in Figure 4. Therefore, it is possible to determine the insertion state depending on the amount of light detected by sensor 147. For example, by comparing the detected amount of light with a threshold, it can be determined whether the insertion state is normal or not.

In the state shown in Figure 4, there is a possibility that the wagon 500 is mounted tilted. In such a case, the mobile robot 100 determines that the wagon is not mounted properly, and therefore determines that there is a mounting abnormality. On the other hand, in Figure 3, the mobile robot 100 determines that the wagon is mounted properly. The mobile robot 100 can detect whether the wagon is mounted properly or not.

There are cases where the mobile robot 100 is unable to move accurately to the underside of the wagon 500. For example, with an autonomous mobile robot 100, the positioning accuracy of movement may not be high enough. If the movement position of the mobile robot 100 relative to the wagon 500 deviates from the normal mounting position, it may not be possible to mount it correctly. For example, as shown in Figure 5, the wagon 500 may become tilted.

A sensor 147 is installed in the positioning unit 141, making it possible to determine whether the mounting condition is normal. The relative positional accuracy of the mobile robot 100 and the wagon 500 is improved simply by raising and lowering the lifting stage 140. Furthermore, in the event of a mounting abnormality, the operation unit 130 may sound an alert.

Sensor 147 is disposed on the side of recess 145. In other words, sensor 147 is disposed sideways. This allows sensor 147 to be installed with its light-emitting and light-receiving parts facing sideways. This prevents the effects of dust and other contaminants, improving detection accuracy. For example, dust may accumulate or dirt may adhere to the bottom of recess 145. If dust accumulates or dirt adheres to the light-receiving or light-emitting parts, the amount of light detected will change. By placing sensor 147 on the side of recess 145, the effects of dust and other contaminants can be reduced. This reduces changes in the amount of light, preventing false detection.

The sensor 147 may be provided in only some of the recesses 145 of the multiple positioning portions 141. In other words, the sensor 147 may be provided in only one of the recesses 145 of the two positioning portions 141 shown in Figure 1. This allows for a reduction in the number of sensors 147, thereby simplifying the device configuration.

Furthermore, the tip 512 of the positioning pin 510 has a curved surface that becomes smaller towards the tip. Specifically, the tip 512 is hemispherical. This improves detection accuracy. For example, the inclination angle of the tip 512 at the light projection position from the sensor 147 changes depending on the height (insertion depth), insertion angle, and insertion position of the positioning pin 510. Therefore, when the position or angle of the positioning pin changes, the amount of light detected by the sensor 147 changes significantly. In other words, when the mounting position or mounting angle of the wagon 500 changes, the amount of light detected by the sensor 147 changes significantly. This allows the mobile robot 100 to accurately determine whether something is normal or abnormal.

Furthermore, the surface of the positioning pin 510 may be a color suitable for detection. For example, it is preferable that the positioning pin 510 be formed in a color that absorbs light. This can improve detection accuracy. Specifically, the positioning pin 510 may be formed in a color such as blue or gray. In other words, the reflectance and absorption rate of the positioning pin 510 can be changed to make it easier to detect the insertion state. Of course, the entire positioning pin 510 may be the same color, or the color may be changed partially. For example, the color of only the tip 512 may be changed. Alternatively, the color may be changed to create a gradation depending on the position of the positioning pin 510 in the Z direction.

At least the area corresponding to the light projection position of the sensor 147 may be a desired color. Furthermore, the degree of specularity or shade of the tip 512 may be changed. Furthermore, fine irregularities may be formed on the surface of the tip 512 to make detection easier. For example, the positioning pin 510 may be colored a desired color, or a resin material of a desired color may be used. Furthermore, the recess 145, tapered surface 143, and installation hole 146 may be colored black, for example, to reduce the effect of scattered light. This can improve detection accuracy.

A tapered surface 143 is also formed around the recess 145. The tapered surface 143 is located between the recess 145 and the mounting surface 142. The tapered surface 143 widens as it goes upward. This allows the positioning pin 510 to be securely inserted into the recess 145. For example, the surface of the tapered surface 143 can be made to have a low coefficient of friction.

Depending on the positional accuracy of the mobile robot 100's movement, the positions of the mobile robot 100 and the wagon 500 may deviate from the correct mounting position. If the lift stage 140 is raised while the mobile robot 100 is deviated from the correct mounting position, the positioning pin 510 comes into contact with the tapered surface 143. By reducing the friction of the tapered surface 143, the positioning pin 510 slides along the tapered surface 143 and is inserted into the recess 145. In this way, the mobile robot 100 can reliably mount the wagon 500.

The number of positioning units 141 provided on the lifting stage 140 is not limited to two. The lifting stage 140 may be provided with one or more positioning units 141. Therefore, the lifting stage 140 may be provided with three or more positioning units 141. If the lifting stage 140 is provided with two or more positioning units 141, it is sufficient that at least one of the positioning units 141 is provided with a sensor 147.

Figure 6 is a block diagram showing the control system of the mobile robot 100. The mobile robot 100 is equipped with a sensor 147, an elevator mechanism 149, a detection unit 160, and a drive control unit 161. The drive control unit 161 controls the wheels 111 to move the mobile robot 100. For example, the drive control unit 161 outputs a command value for the drive motor of the wheels 111 so that the mobile robot 100 moves along a path.

The lifting mechanism 149 raises and lowers the lifting stage 140, thereby changing the height of the mounting surface 142. As described above, the sensor 147 detects the reflected light from the positioning pin 510. The detection unit 160 detects that the positioning pin 510 is inserted into the recess 145 based on the amount of light detected by the sensor 147. Specifically, the detection unit 160 determines whether the insertion state of the positioning pin 510 is normal or not based on the amount of light detected. If the detection unit 160 detects that the insertion state is normal, it determines that the wagon is properly loaded. The detection unit 160 compares the amount of detected light with a threshold value and makes a determination based on the comparison result.

For example, if the detected light amount is lower than the threshold, the detection unit 160 determines that there is an abnormality in the installation. Alternatively, the detection unit 160 may set upper and lower limits for the threshold. If the detected light amount is equal to or greater than the upper threshold or equal to or less than the lower threshold, the detection unit 160 determines that there is an abnormality in the installation. In other words, if the detected light amount is between the upper and lower thresholds, the detection unit 160 determines that there is a normality.

If the positioning pin 510 is not properly inserted into the recess 145, the detection unit 160 determines that a loading error has occurred. If a loading error is determined, the lifting mechanism 149 operates to retry loading. When the lifting mechanism 149 lowers the lifting stage 140, the loading surface 142 also lowers. This causes the positioning pin 510 to disengage from the recess 145. Then, when the lifting mechanism 149 raises the lifting stage 140 again, the positioning pin 510 is inserted into the recess 145.

In addition, before raising the lifting stage 140 again, the drive control unit 161 may drive the wheels 111 to perform alignment. In other words, the drive control unit 161 may drive the wheels 111 to move the mobile robot 100. For example, the mobile robot 100 may move away from the wagon 500 and then move under the wagon 500. The drive control unit 161 may also determine the amount and direction of adjustment for alignment based on the detection results of the sensor 147. This allows for fine adjustment of the position of the mobile robot 100.

Figure 7 is a flowchart showing the operation of the mobile robot 100 to load the wagon 500. First, the mobile robot 100 moves to the wagon's coupling position (S101). The coupling position is located in front of the wagon 500. At the start of processing, the number of lifts is 0. The mobile robot 100 moves under the wagon 500 (S102). The lifting stage 140 lifts up the wagon 500 (S103). In other words, the lifting mechanism 149 raises the lifting stage 140. In step S103, the number of lifts is incremented.

Next, the detection unit 160 determines whether the sensor value is normal (S104). That is, the detection unit 160 compares the amount of light detected by the sensor with a threshold value. The detection unit 160 determines whether the sensor value is within the normal range defined by the threshold value. If the sensor value is normal (YES in S104), the loading operation is terminated. In other words, the mobile robot 100 has successfully loaded the wagon 500, and the mobile robot 100 begins moving to the destination.

If the sensor value is not normal (NO in S104), the lifting stage 140 lifts down the wagon 500 (S105). That is, the lifting mechanism 149 lowers the lifting stage 140. Next, the detection unit 160 determines whether the lift has been performed N times or less (S106), where N is an integer greater than or equal to 1. If the lift has been performed N times or less (YES in S106), the lifting stage 140 lifts up the wagon 500 again (S103).

If the lift has not been performed N times or less (NO in S106), the mobile robot 100 moves to the coupling position (S101). That is, the mobile robot 100 moves out from directly below the wagon 500 and moves to just in front of the wagon 500. Then, the process from step S102 is repeated. In this way, the wagon 500 can be loaded normally.

The mobile robot 100 may use machine learning models such as deep learning for route search and control of the drive control unit 161.

Furthermore, some or all of the processing in the mobile robot 100 described above can be implemented as a computer program. Such programs can be stored and supplied to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible recording media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R/Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). Furthermore, programs may be supplied to a computer by various types of temporary computer-readable media. Examples of temporary computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire or optical fiber, or via a wireless communication path.

The present invention is not limited to the above-described embodiments, and modifications can be made as appropriate without departing from the spirit of the invention. For example, while the above-described embodiments describe a system in which a mobile robot moves autonomously within a hospital, the above-described system can also transport specified items as luggage in hotels, restaurants, office buildings, event venues, or complexes.

The present invention is not limited to the above-described embodiment, and modifications can be made as appropriate without departing from the spirit of the invention.

REFERENCE SIGNS LIST 1 Conveying system 100 Mobile robot 110 Chassis 111 Wheels 120 Stand 130 Operation unit 140 Lifting stage 141 Positioning unit 142 Placement surface 143 Tapered surface 145 Recess 146 Installation hole 147 Sensor 149 Lifting mechanism 160 Detection unit 161 Drive control unit 500 Wagon 510 Positioning pin 512 Tip

Claims (8)

a wagon having a plurality of protrusions protruding downward ;
a mobile robot that moves while carrying the wagon ,
The mobile robot is
a stage having a placement surface on which the wagon is placed and adapted to move under the wagon;
an elevation mechanism that elevates the stage so as to change the height of the placement surface, which is the upper surface of the stage, in order to transfer the wagon;
a plurality of recesses formed on the mounting surface corresponding to the plurality of protrusions and recessed below the mounting surface;
an optical sensor provided on a side surface of at least one of the recesses;
a detection unit that detects whether the convex portion is inserted into the concave portion according to a detection result by the optical sensor,
the stage rises to lift the wagon, so that the mobile robot carries the wagon;
the optical sensor includes a light-projecting unit that projects light toward the recessed portion and a light-receiving unit that detects light reflected by the protruding portion,
The light-emitting unit and the light-receiving unit are arranged facing laterally,
The tip of the convex portion is curved and becomes smaller as it approaches the tip,
the optical sensor is installed at a height where the convex portion forms the curved surface;
Conveying system. The transport system described in claim 1 compares the amount of light detected by the optical sensor with a threshold value to determine whether the insertion state is normal. The conveying system described in claim 1, wherein the optical sensors are provided in only some of the plurality of recesses. The transport system described in claim 1 or 2, wherein a tapered surface that widens upward is provided between the mounting surface and the recess. The transport system described in claim 1 or 2, wherein the recesses are arranged diagonally on the loading surface. A conveying system as described in claim 1 or 2, in which if the positioning convex portion does not fit into the concave portion, a loading error is determined and the system temporarily moves away and then retries. A transport system as described in claim 1 or 2, wherein the surfaces of the convex portions are formed with a light-absorbing color. The conveying system described in claim 1 or 2, wherein the detection unit performs detection based on changes in the amount of light detected by the optical sensor.